Littlejohn MCP server

Little John

Little John is a local Robinhood Chain MCP application and interactive CLI. It reads assets and contracts, constructs USDG / Stock Token exchange decisions, requests the directly confirmed transaction in Robinhood Wallet, and records received hashes and actual transaction results locally.

This document describes the source checkout. For an installed published artifact, use the documentation at that release's source revision.

The current support projection is in Product Policy. Exchange actions are implemented. Robinhood Wallet transaction and replacement behavior is not qualified. The package makes no executable or receipt-verified support claim. Data signing supports personal messages and EIP-712 typed data through direct App controls and interactive CLI. Physical qualification with Robinhood Wallet and each MCP Host application is incomplete.

Install a published release

Use Node.js satisfying the package's engines field:

npm install --global @zktx.io/littlejohn-mcp
littlejohn --help

Install from source

From a repository checkout using the same Node.js requirement:

npm ci
LITTLEJOHN_RELEASE_OUTPUT=/absolute/path/littlejohn-mcp.tgz npm run release:check
npm install --global /absolute/path/littlejohn-mcp.tgz
littlejohn --help

The release check creates the tarball only after its automated package checks pass. It does not publish to npm or qualify a physical Wallet. SQLite is an npm dependency; a separate SQLite server or command-line installation is unnecessary. Its native addon installation remains part of the npm install. An installation error must be resolved before starting the program.

Connect an MCP Host

MCP Host terminology is defined in Architecture.

Configure a local stdio server named littlejohn in the MCP Host's MCP settings:

{
  "mcpServers": {
    "littlejohn": {
      "command": "littlejohn",
      "args": []
    }
  }
}

Use the installed executable's absolute path if the MCP Host does not inherit the shell's executable search path. No website, public server, browser login, or navigable loopback page is needed. The no-argument process serves MCP; CLI commands use the same local backend and Wallet session.

For an optional RPC endpoint, add LITTLEJOHNRPCURL to that server's environment. Omitting it uses Runtime's public default. Do not set an empty string. A supplied URL must pass the current HTTPS configuration admission; failure does not switch to another provider. Keep URLs containing credentials in the MCP Host's secure configuration rather than command arguments. The standard setup field is in server.json.

LITTLEJOHNDATADIR selects a different local profile directory. LITTLEJOHNWALLETCONNECTPROJECT_ID overrides the Wallet adapter's project ID. All processes sharing a profile must use the same configuration. The backend uses its fixed loopback port; a foreign owner is an error, not a reason to select another port. Complete configuration behavior belongs to Architecture.

Backend lifetime and maintenance

Normal MCP and CLI use automatically start an independent local backend. It keeps the Wallet session and pending work alive after a Host closes its MCP connection. The background Node process and its SDK worker continue using memory and local files until explicitly stopped, terminated by the operating system, or stopped by a fatal backend failure. There is no idle shutdown.

Use the same profile and configuration as the connected clients:

littlejohn runtime status --json
littlejohn runtime stop --json

Shortened. The full README is on GitHub.